The present invention relates to a powder of cured fluorosilicone rubber particles suitable as an additive to a variety of compositions such as paints, synthetic resins, synthetic and natural rubbers, polishing agents, surface-release agents and cosmetic or toiletry preparations. This invention also relates to cosmetic preparations compounded with such a powder.
Fine particles of a cured silicone rubber are known in the prior art as disclosed, for example, in Japanese Patent Publications 3-30620, 4-17986, 4-55611, 6-2820, 6-2821 and 6-11795 and elsewhere. Proposals are made for the application thereof as an additive to a thermosetting epoxy resin, synthetic rubber, pigment, coating composition and others. Furthermore, a proposal is made in Japanese Patents Kokai 7-258026, 7-258027, 8-259419, 8-310915, 8-319215 and 8-319218 for the application of cured silicone rubber particles as an additive to a variety of cosmetic products.
Cosmetic products prepared by compounding conventional cured silicone rubber particles have a serious problem. While it is sometimes the case that a cosmetic preparation is formulated with an oily ingredient such as low molecular weight silicones having cyclic or linear molecular structures including octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane and octamethyltrisiloxane and oily hydrocarbon compounds including liquid paraffin and isoparaffin, namely, these oily ingredients are absorbed by the cured silicone rubber particles resulting in swelling of the particles and consequently leading to a decrease in the opacity of the cosmetic layer on the human skin rendering the complexion of the base skin as see-through more or less. Moreover, the rubber particles in the cosmetic finishing layer on the skin are subject to migration under perspiration or by the movement of the face accompanying the coloring agent in the cosmetic preparation resulting in heavy collapsing of the makeup finish.
It is eagerly desired therefore to develop novel and improved cured silicone rubber particles suitable as additives to cosmetic preparations to be free from the above described problems of conventional cured silicone rubber particles without decreasing the advantages to be obtained by the formulation with fine cured silicone rubber particles.